Doctor blade

Abstract

Provide a doctor blade that is less likely to generate sparks when it contacts the surface of a roll. 【Solution means】Both ends of the front end portion 1a of the doctor blade 1 that contacts the surface 2a of the roll 2 in the left-right direction X are chamfered in an arc shape.

Description

Technical Field

[0001] The present invention relates to a doctor blade used for peeling paper from the surface of a roll provided in a papermaking apparatus such as a paper machine.

Background Art

[0002] Generally, in the dryer part of a papermaking apparatus, water-containing paper is continuously supplied to the surface of a roll such as a Yankee dryer heated to a high temperature, and the water-containing paper is dried while being rotated and moved on the roll as the roll rotates. After that, the dried paper is peeled off from the surface of the roll and sent to the next process.

[0003] At this time, a doctor blade is used to peel the paper from the surface of the roll. For example, Patent Document 1 and Patent Document 2 disclose a plate-shaped doctor blade used in a papermaking apparatus such as a paper machine. By pressing the tip of the doctor blade against the surface of the rotating roll, the paper and paper powder dried and adhered to the surface of the roll can be peeled off.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, as described in Patent Document 1, when the doctor blade is made of metal, there is a possibility that sparks may be generated when the tip of the doctor blade contacts the surface of the rotating roll, and the risk of fire due to such sparks has been pointed out. In particular, since there are a large number of sheets of paper and paper dust formed in a sheet shape around the paper manufacturing apparatus, there is a risk that the sparks may ignite those papers and paper dust. Therefore, in Patent Document 1 and Patent Document 2, doctor blades using materials such as epoxy resin, ceramics, and carbon fiber, which are non-metals that do not generate sparks, have been proposed. However, from the viewpoints of high rigidity and durability, the demand for metal doctor blades is high, and there is a need for a doctor blade that is made of metal and is less likely to generate sparks.

[0006] Therefore, an object of the present invention is to provide a doctor blade that is less likely to generate sparks when brought into contact with the surface of a roll.

Means for Solving the Problems

[0007] The doctor blade of the present invention is a plate-shaped one used for peeling paper from the surface of a roll provided in a paper manufacturing apparatus, having a longitudinal direction along the axial direction of the roll, and comprising a rectangular main body including a front end portion that contacts the surface of the roll, a rear end portion that faces away from this front end portion, and side end portions that are both ends in the longitudinal direction. Both ends in the longitudinal direction of the front end portion are chamfered in an arc shape.

[0008] The doctor blade of the present invention is characterized in that both ends in the longitudinal direction of the rear end portion are chamfered in an arc shape.

Effects of the Invention

[0009] The doctor blade of the present invention has both ends in the longitudinal direction of the front end portion chamfered in an arc shape. Therefore, for example, when the front end portion is not chamfered in an arc shape, corners are formed at both ends of the front end portion, and this corner becomes a resistance when the front end portion is brought into contact with the surface of the roll, causing sparks to occur. However, in the case of the doctor blade of the present invention, since the front end portion is chamfered in an arc shape and there is no corner that causes the generation of sparks, the resistance when contacting the surface of the roll is reduced, and the generation of sparks can be suppressed.

[0010] Both ends in the longitudinal direction of the rear end portion of the doctor blade of the present invention are chamfered in an arc shape. Then, for example, when damage such as deformation or chipping occurs at the front end portion and it becomes difficult to use as it is, the rear end portion can be used by contacting the surface of the roll instead of the front end portion. Furthermore, even when the rear end portion is brought into contact with the surface of the roll, since both ends of the rear end portion are chamfered in an arc shape and there is no corner that causes the generation of sparks, the resistance when contacting the surface of the roll is reduced, and the generation of sparks can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0012] Hereinafter, with reference to FIGS. 1 and 2, the doctor blade 1 according to the embodiment of the present invention will be described. In the following description, the axial direction of the roll 2 shown in FIG. 1 and the longitudinal direction of the doctor blade 1 shown in FIG. 2 are taken as the left-right direction X, and the short-side direction of the doctor blade 1 is taken as the front-rear direction Y for explanation.

[0013] FIG. 1 is a schematic perspective view of a state in which the front end portion 1a of a doctor blade 1 is abutted against the surface 2a of a metal roll 2 such as a Yankee dryer provided in a dryer part of a papermaking apparatus (not shown) such as a paper machine. The doctor blade 1 is made of a metal such as iron or stainless steel and is formed in a plate shape. The doctor blade 1 is installed with respect to the roll 2 as shown in FIG. 1 and is used to peel paper from the surface 2a of the roll 2.

[0014] The doctor blade 1 includes a main body 1b. The main body 1b has a longitudinal direction in the left-right direction X which is a direction along the axial direction of the roll 2, a front end portion 1a that abuts against the surface 2a of the roll 2 during installation, a rear end portion 1a' that faces away from the front end portion 1a, and side end portions 1c, 1c which are both ends in the left-right direction X, and is formed in a rectangular shape in plan view (FIG. 2). The front end portion 1a is the front edge of the main body 1b and abuts against the surface 2a of the roll 2 when the doctor blade 1 is installed as shown in FIG. 1. Also, each side end portion 1c, 1c is the left and right edges of the main body 1b and is connected to the front end portion 1a and the rear end portion 1a'. Although not shown, it is desirable that the front end portion 1a be formed as a blade with a thickness thinner than that of the central portion of the main body 1b, and various shapes such as a parallel blade, an inclined blade, a round blade, and a square blade can be used for the blade tip shape.

[0015] Also, both ends in the longitudinal direction (left-right direction X) of the front end portion 1a are chamfered in an arc shape (FIG. 2). Specifically, referring to the partial enlarged view shown in FIG. 2 and taking the right end side of the doctor blade 1 as an example, a first connecting portion 1d connected to the side end portion 1c is formed at the right end of the front end portion 1a. Since the first connecting portion 1d is chamfered in an arc shape toward the side end portion 1c, in the doctor blade 1, the linear front end portion 1a and the linear side end portion 1c are smoothly connected without forming a corner. The doctor blade 1 is formed symmetrically left and right, and a first connecting portion 1d similar to the right end side is also formed on the left end side. However, since the configuration is the same as that on the right end side, the description of the left end side is omitted.

[0016] Further, the rear end portion 1a' is the rear edge of the main body 1b. For example, when damage such as deformation or chipping occurs at the front end portion 1a and it becomes difficult to use as it is, it can be made to abut against the surface 2a of the roll 2 instead of the front end portion 1a. Note that it is desirable that the rear end portion 1a' is also formed as a blade, similar to the front end portion 1a.

[0017] Furthermore, in the doctor blade 1, both ends in the longitudinal direction (left - right direction X) of the rear end portion 1a' are chamfered in an arc shape (Figure 2). Specifically, referring to the partially enlarged view shown in Figure 2 and taking the right - hand side of the doctor blade 1 as an example, a second connecting portion 1e connected to the side end portion 1c is formed at the right end of the rear end portion 1a'. Since this second connecting portion 1e is chamfered in an arc shape towards the side end portion 1c, in the doctor blade 1, the straight rear end portion 1a' and the straight side end portion 1c are smoothly connected without forming a corner. Note that the doctor blade 1 is formed symmetrically left - right, and a second connecting portion 1e similar to the right - hand side is also formed on the left - hand side. However, since the configuration is the same as that on the right - hand side, the description of the left - hand side is omitted.

[0018] Next, the operation and effect of the doctor blade 1 will be described. In the doctor blade 1, both left and right ends of the front end portion 1a are chamfered in an arc shape. Then, since there are no corners that cause the generation of sparks at each of the first connecting portions 1d, 1d which are the two ends of the front end portion 1a, the resistance when the front end portion 1a is brought into contact with the surface 2a of the roll 2 is reduced, and the generation of sparks can be suppressed.

[0019] Further, the doctor blade 1 has a rear end portion 1a' that can be brought into contact with the surface 2a of the roll 2 instead of the front end portion 1a, and both left and right ends of this rear end portion 1a' are chamfered in an arc shape. Then, for example, when damage such as deformation or chipping occurs at the front end portion 1a and it becomes difficult to use as it is, the rear end portion 1a' can be brought into contact with the surface 2a of the roll 2 instead of the front end portion 1a. Further, even when the rear end portion 1a' is brought into contact with the surface 2a of the roll 2, since there are no corners at the respective second connecting portions 1e, 1e which are both ends of the rear end portion 1a' that can cause the generation of sparks, the resistance when the rear end portion 1a' is brought into contact with the surface 2a of the roll 2 is reduced, and the generation of sparks can be suppressed. Also, if it is the doctor blade 1 provided with the rear end portion 1a', it can be used longer compared to other doctor blades, and the replacement frequency can be reduced, so that the maintenance management cost of the paper-making apparatus can also be reduced.

[0020] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above embodiments. And the present invention can be variously designed without departing from the matters described in the claims for utility model registration.

[0021] For example, although the doctor blade 1 according to the present embodiment is configured to have the rear end portion 1a', it may not have the rear end portion 1a'. Also, in the doctor blade 1 according to the present embodiment, an example is shown in which each first connecting portion 1d, 1d which are both ends of the front end portion 1a and each second connecting portion 1e, 1e which are both ends of the rear end portion 1a' are chamfered in an arc shape toward the respective side end portions 1c, 1c. However, each first connecting portion 1d, 1d and each second connecting portion 1e, 1e do not necessarily need to be connected to the respective side end portions 1c, 1c in an arc shape, and it is sufficient that they are chamfered in an arc shape to such an extent that no corners are formed at both ends of the front end portion 1a and both ends of the rear end portion 1a'.

Explanation of Reference Numerals

[0022] 1 Doctor blade 1a Front end portion 1a' Rear end portion 1b Main body 1c Side end portion 1d First connecting part 1e Second connecting part 2 Roll 2a Surface X Left - right direction Y Front - back direction

Claims

1. A plate-shaped doctor blade used for peeling paper from the surface of a roll provided in a papermaking apparatus, comprising a rectangular main body having a longitudinal direction along the axial direction of the roll, a front end portion that contacts the surface, a rear end portion that faces away from the front end portion, and side end portions that are both ends in the longitudinal direction, wherein both ends of the front end portion in the longitudinal direction are chamfered in an arc shape, characterized by the doctor blade.

2. Both ends of the rear end portion in the longitudinal direction are chamfered in an arc shape, characterized by the doctor blade according to claim 1.

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